The wear of a tyre of an aircraft depends on the number of landings and takeoffs to which it is subjected. The number of landings is equal to the number of takeoffs.
On the one hand, it is desirable for the manufacturer to know this number of landings or of takeoffs in order to monitor the wear of the tyres and to appreciate the variation in the performance of the tyres as a function of the wear of the latter. On the other hand, it is desirable for the various actors intervening on the aircraft (maintenance services, inspection services, etc.) to be able to anticipate the change or the retreading of a worn tyre.
From the document FR 2 939 897, a method and a device is known for counting the number of landings of a aircraft tyre. The device is attached to an internal surface of the tyre. The device comprises a sensor and means for powering the device, for example a battery. The sensor comprises a coil sensitive to the time variations in magnetic flux generated by the rotation of the tyre in the Earth's magnetic field or in a local magnetic field generated for example by a magnet. The coil then generates a periodic signal whose frequency is equal to the frequency of rotation of the tyre. During the method, the frequency of rotation of the tyre is measured. When the frequency of rotation exceeds a predetermined threshold, in other words during a landing or takeoff phase, the number of landings is incremented.
However, in order to measure the frequency of rotation of the wheel, the sensor continuously measures the signal generated by the coil, which is very energy-hungry. Thus, in view of its high energy consumption, the device has a lifetime limited to 2 years using a battery with a capacity of 550 mA·h and weighing 8 g. It is therefore necessary to change the power supply means at each retreading. In order to avoid a change of the power supply means at each retreading, the capacity of the power supply means can be increased which inevitably increases the weight. However, the increase in the weight results in too high a mass imbalance during the rotation of the tyre at high speed.